>From 5295e0fb786bb20411d14a88fe0195672f1e0dd6 Mon Sep 17 00:00:00 2001
From: Bron Gondwana <brong@fastmail.fm>
Date: Sun, 25 Jan 2009 21:43:36 +1100
Subject: [PATCH] epoll: also show owner uids in epoll/limits output

So - the data is in epoll/limits is probably more useful if the uid
of each of the maximum counts is available for easy tracking down.
This patch adds it.
---
 fs/eventpoll.c            |    6 ++++--
 include/linux/eventpoll.h |    5 ++++-
 kernel/user.c             |   13 ++++++++++---
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index f9cba5b..2113795 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -259,7 +259,9 @@ static int zero;
 static int epoll_user_instances(ctl_table *table, int write, struct file *filp,
                      void __user *buffer, size_t *lenp, loff_t *ppos)
 {
-        user_epoll_maximums(&epoll_limits.num_user_instances, 
+        user_epoll_maximums(&epoll_limits.instances_uid,
+                            &epoll_limits.num_user_instances, 
+                            &epoll_limits.watches_uid,
                             &epoll_limits.num_user_watches);
         return proc_dointvec(table, write, filp, buffer, lenp, ppos);
 }
@@ -284,7 +286,7 @@ ctl_table epoll_table[] = {
 	{
 		.procname	= "limits",
 		.data		= &epoll_limits,
-		.maxlen		= 4*sizeof(int),
+		.maxlen		= 6*sizeof(int),
 		.mode		= 0444,
 		.proc_handler	= &epoll_user_instances,
 		.extra1		= &zero,
diff --git a/include/linux/eventpoll.h b/include/linux/eventpoll.h
index 38bec62..8258d0a 100644
--- a/include/linux/eventpoll.h
+++ b/include/linux/eventpoll.h
@@ -61,7 +61,9 @@ struct file;
  * Configuration options available inside /proc/sys/fs/epoll/
  */
 struct epoll_limits_struct {
+	uid_t instances_uid;             /* read only */
         int num_user_instances;          /* read only */
+	uid_t watches_uid;               /* read only */
         int num_user_watches;            /* read only */
         int max_user_instances;          /* tunable */
         int max_user_watches;            /* tunable */
@@ -107,7 +109,8 @@ static inline void eventpoll_release(struct file *file)
 }
 
 extern struct epoll_limits_struct epoll_limits;
-extern void user_epoll_maximums(int *num_devs, int *num_watches);
+extern void user_epoll_maximums(uid_t *user_devs,    int *num_devs, 
+                                uid_t *user_watches, int *num_watches);
 
 #else
 
diff --git a/kernel/user.c b/kernel/user.c
index 4d03a95..ef8769a 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -382,7 +382,8 @@ struct user_struct *find_user(uid_t uid)
 }
 
 #ifdef CONFIG_EPOLL
-void user_epoll_maximums(int *max_devs, int *max_watches)
+void user_epoll_maximums(uid_t *user_devs,    int *max_devs, 
+                         uid_t *user_watches, int *max_watches)
 {
 	unsigned long flags;
 	struct user_struct *user;
@@ -390,16 +391,22 @@ void user_epoll_maximums(int *max_devs, int *max_watches)
 	int n;
 
 	*max_devs = 0;
+	*user_devs = root_user.uid;
 	*max_watches = 0;
+	*user_watches = root_user.uid;
 
 	spin_lock_irqsave(&uidhash_lock, flags);
 
 	for(n = 0; n < UIDHASH_SZ; ++n) {
 		hlist_for_each_entry(user, h, init_user_ns.uidhash_table + n, uidhash_node) {
-			if (user->epoll_devs.counter > *max_devs) 
+			if (user->epoll_devs.counter > *max_devs) {
 				*max_devs = user->epoll_devs.counter;
-			if (user->epoll_watches.counter > *max_watches) 
+				*user_devs = user->uid;
+			}
+			if (user->epoll_watches.counter > *max_watches) {
 				*max_watches = user->epoll_watches.counter;
+				*user_watches = user->uid;
+			}
 		}
 	}
 
-- 
1.5.6.3